refactor(api): migrate console tag responses from marshal_with to BaseModel

[ai-hpc]

Part of #28015

Summary

Replace @marshal_with in console tag list response path with Pydantic BaseModel serialization. Add TagResponse schema registration and normalize enum-backed type values while keeping endpoint response shape unchanged.

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint and make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

[github-actions]

Pyrefly Diff

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[Copilot]

Pull request overview

Refactors the console tag endpoints to stop using Flask-RESTX @marshal_with for the tag list response and instead serialize responses via Pydantic BaseModel (via ResponseModel), while registering the response schema for API documentation.

Changes:

• Introduces TagResponse(ResponseModel) and registers it with console_ns for schema docs.
• Updates GET /tags to return a list of TagResponse-serialized dicts instead of relying on @marshal_with.
• Adds a unit test to verify TagResponse normalizes enum-backed type values during JSON serialization.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
api/controllers/console/tag/tags.py	Replaces @marshal_with response marshalling with Pydantic serialization; adds TagResponse schema + normalization validator.
api/tests/unit_tests/controllers/console/tag/test_tags.py	Adds a unit test covering TagResponse enum normalization behavior.

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[github-actions]

Pyrefly Diff

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[ai-hpc]

@asukaminato0721 please merge